The P20CB Code is found in the car engine for the engine problem and it should be removed by solving the car engine problem. Fixing the car engine is easy if it is related with the body or with the chassis. You need to get the meaning regarding the code. According to your car brand, you need to seek the appropriate meaning of the code and then you can solve the problem if you have all machines and experience. Do not think to solve the car engine problem according to the general meaning of the code. It may force to you to face more serious problem.